Polar Bear

Range:

U.S. (Alaska), Canada, Russia, Greenland, and Norway.

Habitat:

Lives on Arctic ice, tundra, woodlands and along coastal shores.

Characteristics:

Compared to other bears, polar bears have more slender bodies and longer necks and heads. Their coat can vary from pure white to yellow to light brown depending upon season and angle of light. Their hind limbs are longer than the forelimbs. This makes their large, muscular hind end stand higher than the shoulders. Their feet are five-toed paws with strong curved claws. The pads are furred and are covered with small bumps called papillae to keep them from slipping on ice.

A polar bear's fur coat is about 1-2 inches thick. A dense, woolly, insulating layer of under hair is covered by a relatively thin layer of stiff, shiny, hollow guard hairs. Guard hairs may be as long as 6 inches. The hair is hollow and is translucent, however, it appears white because of their ability to reflect light.

The fur is oily and water repellant. It doesn’t mat when wet and allows the bear to easily shake off water or ice. A polar bear's skin is black. The black color enables the bear to absorb sunlight energy to warm its body. Polar bears are insulated by two layers of fur that help keep them warm. They also have a thick fat layer. In addition, their small ears and tail also prevent heat loss.

Behavior:

Polar bears are active any time of the day or night. On bitterly cold days, they might dig a hole, curl up and even cover their noses with their paws to keep warm. In warmer weather they might also burrow into the earth to keep cool.

Polar bears walk at about three miles per hour. Females with small cubs move more slowly. Despite their plodding gait, they can move as quickly as a horse when necessary—up to 24 miles per hour for short distances. Moving in the harsh climate burns a lot of calories. In fact, research has shown that a walking bear expends 13 times more energy than a resting bear. Older, larger bears quickly overheat when running.

To find their food, the bears locate breathing holes with their powerful sense of smell and wait patiently for the seals to rise—from hours to days.

Polar bears depend on ice for access to their prey. In the summer when the ice floes retreat, polar bears follow the ice—sometimes traveling hundreds of miles—to stay with their food source. If they are not able to get onto the ice and become stranded on land they must wait until the ice forms again. During this time they are opportunistic feeders and eat what’s available. They often lose large amounts of weight when stranded.

When seal hunting is good, polar bears eat only the blubber and skin. They can eat 100 pounds of blubber in a single sitting. Younger, less experienced bears devour the remains, as do arctic foxes.

Polar bears use a combination of body language and vocalizations to communicate. These may include head waging, nose-to-nose greeting, chuffing, growling, hissing, snorting and physically attacking another bear.

Polar bears spend a great deal of time grooming. In the summer they will take a swim after feeding and in the winter will roll around in the snow to clean their fur. They will also lick their paws and fur to keep it clean. Anywhere that dirt works its way in is a place that cold air or water can reach their skin, so staying clean is important!

Polar bears are strong swimmers and divers. Because of their adaptations and the amount of time they swim in the water they are classified as marine mammals. They will swim across bays or wide leads without hesitation and can swim for several hours at a time over long distances. They've been tracked swimming continuously for 62 miles. A polar bear's front paws propel them through the water dog-paddle style. The hind feet and legs are held flat and are used as rudders. They can reach a swimming speed of 6 miles per hour.

When swimming the bear’s nostrils close to keep water from entering their lungs. This adaptation aides them when making shallow dives when stalking prey, navigating ice floes, or searching for kelp. They swim beneath the surface of the water at depths up to 14 feet and can hold their breath for up to two minutes. The generally do not dive deeper than 20 feet. They are well insulated to survive the cold water temperatures and will also swim to cool down on warm days or after physical activity.

Reproduction:

Polar bears are solitary animals and mating takes place on the ice in April or May, but the fertile egg do not implant until the following fall. This is called delayed implantation.

A cub is about the size of a rat or pound of butter when it is born. The mother bear digs a cozy den in the snow to have her cubs. The den is no bigger than a telephone booth. The internal den temperature may be 40 degrees Fahrenheit warmer in the den than on the surface of the snow. Usually two cubs are born to each mother between December and January. They are hairless and blind at birth, and depend on their mother to keep them warm and fed.

Milk from polar bear mothers is 35 percent fat, the richest milk of any species of bear. This helps the cubs grow quickly, and by April they weigh more than 20 pounds and start exploring with their mother outside the den. At about two years of age they are ready to be on their own.

Interesting Facts:

Polar bears are built to stay so warm in their cold habitat that sometimes they overheat, and have to cool off in the cold Arctic waters.

These remarkable bears have a transparent eyelid (nictitating membrane) that work like a pair of sunglasses filtering out the excessive brightness of snow and sun. They also work as waterproof goggles underwater.

Polar bears have 42 teeth and are well adapted to their carnivorous diet. Their canines are the largest and longest of any other bear. They use their extremely sharp carnassials and molars for shearing and biting food.

Polar bears are inactive about 87% of the time, living off stored fat. They can go into a "walking hibernation" as a survival mechanism when food sources become scarce.

They keep their eyes open, their nostrils shut and their ears flattened to their heads while swimming and they can stay underwater up to two minutes. They're capable of leaping out of the water seven to eight feet to catch seals or other prey.

About Our Animals:

The Zoo currently is home to one female polar bear named Rizzo.

Conservation:

Today's polar bears are facing rapid loss of the sea ice where they hunt, breed, and, in some cases, den. Changes in their distribution or numbers affect the entire Arctic ecosystem. Scientists believe that we still have time to save polar bears if we significantly reduce greenhouse emissions within the next few years. Yet it will take 30 to 40 years for changes reversing the warming trend to show. You can help by doing simple things like unplugging unused electronics like computers, driving less and by planting trees.

Did YOU Know?

The polar bear's nose is so powerful it can smell a seal on the ice 20 miles away, sniff out a seal\\\\\\\'s den that has been covered with snow, and even find a seal's air hole in the ice up to one mile away.